ATmega16HVB Atmel Corporation, ATmega16HVB Datasheet - Page 124

• Manufacturer Part Number: ATmega16HVB
• Manufacturer: Atmel Corporation

Specifications of ATmega16HVB

• Flash (kbytes): 16 Kbytes
• Pin Count: 44
• Max. Operating Frequency: 8 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 8
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 17
• Ext Interrupts: 15
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 12
• Adc Speed (ksps): 1.9
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 1
• Eeprom (bytes): 512
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 4.0 to 25
• Operating Voltage (vcc): 4.0 to 25
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 2
• Output Compare Channels: 4
• Input Capture Channels: 2
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

21.6
21.6.1
21.6.2
124
Register description
ATmega16HVB/32HVB
BGCCR – Bandgap Calibration C Register
BGCRR – Bandgap Calibration R Register
•
These bits are reserved and will always read as zero.
•
These bits are used for trimming of the nominal value of the bandgap reference voltage. These
bits are binary coded. Minimum VREF: 000000, maximum VREF: 111111. Step size is approxi-
mately 2mV. The application software should read the Atmel factory calibration value and store it
to the BGCCR register. See
•
These bits are used for temperature gradient adjustment of the bandgap reference.
on page 125
coefficient at low temperatures and negative temperature coefficient at high temperatures.
Depending on the process variations, the top of the VREF curve may be located at higher or
lower temperatures. To minimize the temperature drift in the temperature range of interest,
BGCRR is used to adjust the top of the curve towards the centre of the temperature range of
interest. The BGCRR bits are thermometer coded, resulting in 9 possible settings: 00000000,
00000001, 00000011, 00000111, … , 11111111. The value 00000000 shifts the top of the VREF
curve to the highest possible temperature, and the value 11111111 shifts the top of the VREF
curve to the lowest possible temperature. The application software should read the Atmel factory
calibration value and store it to the BGCRR register. See
ware” on page 195
Bit
(0xD0)
Read/Write
Initial Value
Bit
(0xD1)
Read/Write
Initial Value
Bits 7:6 – Reserved
Bit 5:0 – BGCC[5:0]: BG Calibration of PTAT Current
Bit 7:0 – BGCR[7:0]: BG Calibration of Resistor ladder
BGCR7
illustrates VREF as a function of temperature. VREF has a positive temperature
R/W
R
7
–
0
7
0
for details.
BGCR6
R/W
R
6
–
0
6
0
”Reading the signature row from software” on page 195
BGCC5
BGCR5
R/W
R/W
5
0
5
0
BGCC4
BGCR4
R/W
R/W
4
0
4
0
BGCC3
BGCR3
R/W
R/W
3
0
3
1
”Reading the signature row from soft-
BGCC2
BGCR2
R/W
R/W
2
0
2
1
BGCC1
BGCR1
R/W
R/W
1
0
1
1
BGCC0
BGCR0
R/W
R/W
0
0
0
1
8042D–AVR–10/11
Figure 21-2
for details.
BGCCR
BGCRR